There Was a Young Lady Who (Accidentally) Swallowed a Knife
Perhaps she'll be fine.

From the case files of this week's New England Journal of Medicine comes the tale of a woman who noticed "chest discomfort" when a "knife migrated into her esophagus." It's equal parts compelling and tragic. No blood, I promise.
A 30-year-old woman was hanging out with her friends when she became inspired to demonstrate that she no longer had a gag reflex.
Before anyone makes a dumb joke about that, the reason for her stifled reflex was that she had been living with bulimia. If you trigger your gag reflex frequently enough, you can become desensitized to it. People who swallow flaming swords do so purposely, because they want to swallow flaming swords in an elegant manner. (Also, according to research done by dentists, you can temporarily suppress your gag reflex by holding a pressure point on the palm of your hand. Our bodies are like levels in Zelda.)
So the poor young woman grabbed a knife from the table -- a butter knife, goodness -- and used it to probe forcibly, defiantly, along the back of her mouth and tongue. She did put the knife in handle-first, which makes the whole thing sound instantly more practical, actually. Just the image, though, makes me gag.
Poking around in the back of your mouth with the blunt end of a butter knife normally triggers your ninth cranial nerve (glossopharyngeal nerve) to start a rapid reflex loop up to your brainstem and back down through the tenth cranial nerve (vagus nerve) to contract the muscles of the soft palate and pharynx and forcibly expel whatever's back there. Nothing that big and un-chewed belongs back there. That's one of those rare edicts upon which science and the Old Testament unwaveringly agree.
Once she had the knife in the back of her mouth, though, because her reflex was burned-out from her eating disorder, she didn't gag. But she did start to laugh. The report doesn't say why. Maybe someone made a joke. Maybe she was suddenly overwhelmed by the novelty of the entire situation. Maybe it was self-satisfaction, an evil laugh (eLOL) as she realized she'd bested her dinner-mates in party trickery.
Whatever the reason, she laughed, and the knife slid down into her esophagus. The collective gasp was undoubtedly sweeping.
When you laugh hard, your peripheral muscles loosen. That's presumably the reason her hand relaxed to the point that she let go of the knife. (Sometimes people will experience attacks of whole-body loss of muscle tone when laughing. It's called cataplexy. They sink to the ground like jelly. It can be terrifying.)
So her hand relaxed, and she dropped the knife. In that instant she likely tried to reach in after it, but it was an old-fashioned heavy-handled butter knife, and it sank hastily down to her gastroesophageal junction -- out of reach even for one without a gag reflex. ("Dinner-mates! Who has the smallest hands?")
They took her to the hospital straight away. Chest x-rays confirmed her story, as if she'd have reason to lie. (Some people do, though, lie about things like this. It's called Münchausen syndrome.)
The radiologists who interpreted her x-rays where assuredly vigilant in looking not just for the position of the knife, but also in searching for air around her heart, which would indicate that the knife had cut her esophagus. If that happened, she would need urgent surgery. But, good, no air. The knife was enjoying an exasperated stasis in her distal esophagus.
She was nonetheless whisked off to an operatory where a gastroenterologist with a robotic endoscope, equipped with a camera on the tip and a retractable lasso, retrieved the knife. It's a wondrously straightforward procedure. No cutting, no stitches. It went well, and there were no complications.
Almost out of the woods, but not yet. They still needed to test for subtle tears in her esophagus. They had her drink some dense, acrid contrast material while she was under an x-ray camera. The contrast paints the esophagus bright white, so it looks like a lead pipe in the middle of the x-ray. If there are any leaks, they're easily seen. Again, luckily, none.
The overall experience may have been a positive one, as it called attention to the severity of her bulimia. She was seen by a psychiatrist and admitted to a psychiatric unit for treatment. If she hadn't laughed, and the knife hadn't slipped, who knows how much longer that could've gone without proper attention.
On that note, if you or someone you know is suffering from an eating disorder -- and someone you know is -- this is a good place to start for treatment and support groups. In the tone of an ethereal United Way infomercial incantation: Don't wait until they swallow a knife.